OXFORD United have immediate concerns over how long John Mousinho will be out injured after being forced off against Watford.

The club captain had treatment on his right knee after a clash in the opening seconds of the Carabao Cup second-round tie at the Kassam Stadium.

But he was forced off 20 minutes from time in the game, which finished 1-1 before United lost on penalties.

Boss Karl Robinson is worried it is serious.

He said: "We think so, it’s not good.

"Right now it looks like the injury he received against Sunderland. It’s the same knee and the same type of pain."

The game with Watford was only Mousinho's second start since the injury against the Black Cats in February.

And if scans reveal he does face a lengthy spell out, it is likely to add to Robinson's shopping list before the transfer window closes next month.

It continued a bruising few days for the squad, who have lost Alex Gorrin and Josh Ruffels until next month with ankle and shoulder problems respectively.

The United head coach, who is hopeful Matty Taylor will shrug off a hip niggle to face Sunderland on Saturday, said: "I keep getting people falling out through injury.

"We’ll see what the next 48 hours bring. We don’t stop working here, it’s embedded in the staff and players.

"We’ll go away and work hard to see how this picture now looks with Mous out and certain people not available for the weekend."